Traditional disk wipers are often stuck in bad sectors leaving no time to sanitize data on healthy area of the disk, or just skip them leaving sensitive information around bad sectors not erased. WBD(Wipe Bad Disk) can thoroughly wipe disks with bad sectors in a hierarchical and elegant way. Even the disk has no bad sectors, you can also take advantage of the WBD's unique wiping algorithm to gain high security degree in a short time. WBD wipes the disk through 3 stages(stage 0-stage 2), 16 passes, and multiple levels, resulting in a new security-degree to time-cost relationship(see the figure below) in contrast to the linear functional relationship of traditional disk shredding software. This means if you can not wait the wiping process to complete and stop it earlier, you can gain higher security degree than conventional disk wipers costing the same amount of time.